Springs, wheels, axels, tires, and maneuverability are all effected by an overloaded RV. Distribute weight as evenly as possible when loading the RV this is very crucial to being able to control the RV while turning.
If you are using a camper that fits in a truck bed weight distribution is a little different. You want to pay attention to weight distribution limits, center of gravity zones, and also make sure not to create a tail-heavy or top-heavy situation.
So just be aware of how much your are actually loading into your RV and make sure to evenly pack it on each side. To be certain your ride is not too heavy you can always weigh it at a near by business with the right scale.